Wells Matthew P, Bakhit Babak, Fairclough Simon M, Weingard Jordi J H, Ducati Caterina, MacManus-Driscoll Judith L
Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK.
Thin Film Physics Division, Department of Physics (IFM), Linköping University, 58183, Linköping, Sweden.
Nano Converg. 2025 Jul 18;12(1):37. doi: 10.1186/s40580-025-00494-1.
Highly oriented oxide thin films hold substantial relevance to a wide range of fields. A major challenge is their integration with technological substrates, such as flexible polymers and silicon. While multiple strategies for the lift-off and transfer of high-quality oxide thin films have been widely explored, it remains a challenge to easily transfer films with low defect levels. In this work, we introduce a novel and effective strategy for achieving high-quality, freestanding perovskite oxide thin films. We first demonstrate that highly oriented perovskite oxides, as both single-phase films and vertically aligned nanocomposite (VAN) films, can be grown by pulsed laser deposition on single crystal NaCl, as not shown before. We next show that the VAN films, unlike single-phase films, can be readily, electrostatically, dry lifted-off the substrate. The success of the lift-off technique is enabled by (i) a high thermal expansion mismatch of the film, producing compression in the film, and (ii) lack of elastic strain relief in the out-of-plane direction in the VAN film. Finally, we show that a VAN cathode film can be incorporated into a proof-of-concept micro-solid oxide fuel cell structure, and that it is of good structural quality as demonstrated by performance comparable to equivalent VAN films grown on single crystal YSZ. Thus, we developed an entirely new way to lift-off and transfer highly oriented oxide thin films for use in a wide variety of electronic applications.
高度取向的氧化物薄膜与广泛的领域密切相关。一个主要挑战是它们与诸如柔性聚合物和硅等技术衬底的集成。虽然已经广泛探索了多种用于高质量氧化物薄膜剥离和转移的策略，但轻松转移低缺陷水平的薄膜仍然是一个挑战。在这项工作中，我们引入了一种新颖且有效的策略来制备高质量的独立钙钛矿氧化物薄膜。我们首先证明，高度取向的钙钛矿氧化物，无论是单相薄膜还是垂直排列的纳米复合材料（VAN）薄膜，都可以通过脉冲激光沉积在单晶NaCl上生长，这在此前未见报道。接下来我们表明，与单相薄膜不同，VAN薄膜可以很容易地通过静电作用干法从衬底上剥离。剥离技术的成功得益于：（i）薄膜的高热膨胀失配，在薄膜中产生压缩应力；（ii）VAN薄膜在面外方向缺乏弹性应变弛豫。最后，我们展示了VAN阴极薄膜可以被整合到概念验证的微固体氧化物燃料电池结构中，并且其结构质量良好，这通过与在单晶YSZ上生长的等效VAN薄膜相当的性能得以证明。因此，我们开发了一种全新的方法来剥离和转移高度取向的氧化物薄膜，以用于各种电子应用。
